Open Orphan plc announced that hVIVO, a subsidiary of Open Orphan plc, has signed a £5 million influenza human challenge study contract with a biotech company developing an antiviral drug for protection against respiratory viral infections. The study, which is expected to commence in H2 2022, will test and assess the efficacy of a single dosing regimen of the client's antiviral drug, with healthy adult volunteers, using the hVIVO Influenza human challenge study model. Conducted at hVIVO's state-of-the-art facilities in London, Open Orphan expects the majority of revenues to be recognised in 2022. Respiratory tract infections are infections of parts of the body involved in breathing, such as the sinuses, throat, airways or lungs and are often caused by viruses such as influenza. Seasonal influenza causes significant morbidity and mortality each year and a pandemic influenza continues to pose a worldwide threat. Influenza is a serious global health threat with an estimated 1 billion cases per year, 3-5 million severe cases and 290,000 - 650,000 deaths per year. Healthy volunteer human challenge studies of wild-type influenza play a major role in the development of vaccines and therapeutics against influenza. hVIVO has been studying influenza for over 20 years and conducting influenza human challenge studies with its flu disease models for more than 15 years. hVIVO has conducted numerous flu challenge studies for a range of industry, governmental and academic clients, making its models the most well-used commercial flu disease models available on the market. hVIVO also has expertise in safely conducting challenge studies across a range of respiratory viruses, including various strains of Influenza, Respiratory Syncytial Virus (RSV) and human Rhinovirus HRV (common cold virus), malaria, and asthma. In October 2020, this expanded to include the SARS-CoV-2 virus.